The use of online storage services for storing and sharing data is becoming more popular. In general, most contemporary access to Internet storage is based on relatively complicated protocols such as FTP (File Transfer Protocol) that require specific application support.
WebDAV, or simply DAV, (Distributed Authoring and Versioning), is a protocol described in Extensible Markup Language (XML) that extends HTTP (HyperText Transfer Protocol) essentially so that Internet content and the like can be manipulated. For example, although HTTP allows content to be written using the PUT and POST verbs, WebDAV allows querying and manipulation of metadata on the files, using verbs like PROPFIND and PROPPATCH, and LOCKing of files, which along with the HTTP verbs like PUT and POST, allow document manipulation. Intermediate programs have been written to simplify the use of these protocols. For example, Microsoft Corporation's Windows® 95, Windows® 98, and Windows® 2000 operating systems provide “Web Folders,” which act as interfaces to a collection of resources stored on a DAV server. Web Folders appear similar to local file folders, e.g., files can be dragged and dropped into a representation of a Web Folder, and so forth. However, Web Folders cannot be used with a non-modified application program, and only applications that have their code integrated with Web Folders can utilize Web Folders.
Alternatively, a few applications are DAV-aware and are able to work with files on WebDAV servers, such as files appearing in Web Folders. However, such applications require specific support of the protocols to access the data on the Internet, and are generally limited to a few special web authoring tools. The majority of applications, including applications already in existence, are not capable of accessing WebDAV server files, and it is virtually impossible to retroactively adapt such existing application to do so.